Wire bonding capillary tool having multiple outer steps

Abstract

A bonding tool for bonding a fine wire to a substrate, said bonding tool comprising an at least substantially cylindrical portion having a concentric capillary therein through which the fine wire runs; a working tip portion formed at an end of the cylindrical portion being tapered towards the tip thereof, said working tip portion having an annular chamfer at the tip thereof; wherein the concentric capillary opens into the annular chamfer of the working tip, and wherein the diameter of the cylindrical portion decreases consecutively at a plurality of discrete intervals along the length of the cylindrical portion towards the working tip portion.

1 . A bonding tool for bonding a fine wire to a substrate, said bonding tool comprising:
 an at least substantially cylindrical portion having a concentric capillary therein through which the fine wire runs; and   a working tip portion formed at an end of the cylindrical portion being tapered towards the tip thereof, said working tip portion having an annular chamfer at the tip thereof;   wherein the concentric capillary opens into the annular chamfer of the working tip; and   wherein the diameter of the at least substantially cylindrical portion decreases consecutively of at least two discrete intervals along the length of the at least substantially cylindrical portion towards the working tip portion.   
     
     
         2 . The bonding tool according to  claim 1 , wherein the diameter of the at least substantially cylindrical portion decreases consecutively at two discrete intervals. 
     
     
         3 . The bonding tool according to  claim 1 , wherein the diameter of the at least substantially cylindrical portion decreases consecutively at three, four, or five discrete intervals. 
     
     
         4 . The bonding tool according to  claim 1 , wherein the consecutive diametric decrease at each discrete interval comprises any of a step, a tapering, and any combination thereof towards the longitudinal central axis of rotation of the at least substantially cylindrical portion. 
     
     
         5 . The bonding tool according to  claim 4 , wherein the step consists of any of: essentially a ninety degree step, a plurality of tapers, or an arc. 
     
     
         6 . The bonding tool according to  claim 4 , wherein the tapering is angled up to 10 degrees towards the longitudinal central axis of rotation of the cylindrical portion. 
     
     
         7 . The bonding tool according to  claim 4 , wherein the consecutive diametric decrease at each discrete interval is concentric to each other consecutive decrease at each other discrete interval. 
     
     
         8 . The bonding tool according to  claim 1 , wherein the discrete intervals are proportionately or equally distributed over the length of the cylindrical portion. 
     
     
         9 . The bonding tool according to  claim 2 ,
 wherein first and second discrete intervals along the length of the cylindrical portion are distant from the working tip by about 7.10 mm and by about 2.65 mm, respectively, or   wherein the diameter of the at least substantially cylindrical portion decreases at the first and second discrete intervals from about 1.587 mm to about 1.20 mm and from about 1.20 mm to about 0.82 mm, respectively.   
     
     
         10 . The bonding tool according to  claim 1 , wherein the at least substantially cylindrical portion has a latitudinal cross-section that is polygonal, circular, or elliptical. 
     
     
         11 . The bonding tool according to  claim 10 , wherein the latitudinal cross-section that is polygonal is pentagonal in shape, hexagonal in shape, or octagonal in shape. 
     
     
         12 . The bonding tool according to  claim 1 , wherein the at least substantially cylindrical portion and working tip are adapted to undergo an ultrasonic displacement when ultrasonic energy is transmitted to the bonding tool. 
     
     
         13 . The bonding tool according to  claim 12 , wherein the working tip portion has a displacement amplification ratio of at least about three when undergoing ultrasonic displacement. 
     
     
         14 . The bonding tool according to  claim 12 , wherein the ultrasonic displacement of the at least substantially cylindrical portion and working tip is at least substantially sinusoidal. 
     
     
         15 . The bonding tool of  claim 1 , wherein the length of the concentric capillary and annular chamfer is within a range of from about 9.00 mm to about 20.00 mm. 
     
     
         16 . The bonding tool according to  claim 1 , wherein the concentric capillary is of a diameter within a range of from about 80 μm to about 5.0 mm, inclusive. 
     
     
         17 . The bonding tool according to  claim 1 , wherein the concentric capillary is made of a material selected from the group consisting of a metal, a ceramic and/or a ceramic-metallic (CerMet) composite. 
     
     
         18 . The bonding tool according to  claim 17 ,
 wherein the metal is selected from the group consisting of nickel, titanium molybdenum, and cobalt; or   wherein the ceramic is selected from the group consisting of oxides, carbides, nitrides, and borides; or   wherein the CerMet is selected from the group consisting of cobalt bonded tungsten carbide, titanium carbonitride, and titanium nitride.   
     
     
         19 . A bonding system for forming a metallurgical bond between a fine wire and a bonding substrate, said device comprising:
 the bonding tool of  claim 1 ; and   a nano-scale ultrasonic energy source operatively connected to said bonding tool to transmit ultrasonic energy to the bonding tool.   
     
     
         20 . The system of  claim 19 , wherein the bonding substrate is a bond pad or a leadframe.